Effects of preflood nitrogen rate and midseason nitrogen timing on flooded rice

2000 ◽  
Vol 134 (4) ◽  
pp. 379-390 ◽  
Author(s):  
R. CARRERES ◽  
J. SENDRA ◽  
R. BALLESTEROS ◽  
J. GARCÍA DE LA CUADRA

A field study was conducted to investigate the agronomic performance, nitrogen (N) efficiencies, yield components and yield of rice in Spain for different nitrogen treatments. The experimental variants were six preflood N rates (0, 50, 75, 100, 125 and 150 kg/ha) and three topdressing patterns: (i) non- topdressed, (ii) topdressed with 50 kg N/ha at mid-tillering stage (MT) and (iii) topdressed at panicle initiation stage (PI). The N status of the plant was measured at different growing stages to determine whether a chlorophyll meter would be useful in making N sidedress recommendations. The results showed that grain yield increased with increasing amounts of preflooding N fertilizers up to 100 kg N/ha. The main effect was on panicle number per unit ground area. The effect of additional N supply on yield components and grain yield depended on application timing. Split applications of N did not improve the agronomic efficiency but reduced days to maturity and lodging and increased the harvest index value. Split applications increased grain yield when the total N rate was 150 kg/ha with the second supply at PI. There was a significant but not very good relationship between N content and chlorophyll content (SPAD) values. The regression equation differed significantly depending on growth stage. The SPAD value may determine the need for N topdressing at MT stage, but not at PI. However, the relationship between SPAD value and the rice yield increase from N topdressing application was not very good.

Author(s):  
C. P. McCabe ◽  
J. I. Burke

Abstract Factorial experiments were carried out on spring- and winter-sown oat crops in Ireland in 2016–2019 to identify plant responses in yield formation and grain filling procedures. Two cultivars (Husky and Keely), three seed rates (250, 350 and 450 seeds/m2), six applied nitrogen (N) rates (40, 70, 100, 130, 160 and 190 kg N/ha) with a plant growth regulator (PGR) were examined in spring and winter sowings, using the same cultivars at five rates of applied N (80, 110, 140, 170 and 200 kg N/ha). The applied N rate and seed rate significantly (P < 0.05) modified the yield components determining grains/m2 in spring- and winter-sown crops with increases in panicle number of key importance. Increases were also observed in the proportion of primary grain by weight (0.9–1.6%) and number (0.7–1.4%) ratios in spring-sown crops in response to applied N rate, with winter-sown crops exhibiting a more consistent pattern of grain fill. Seed rate and PGR application had minor effects on yield components and panicle conformation. Grain fill procedures played an important role in the maximization of grain yield under seasonal conditions. Significant positive correlations were observed between the number of aborted grain sites and yield under drought conditions (0.22), with negative associations observed in near-optimal conditions (−0.22 to −0.41). Agronomic effects on grain site abortion were minimal in comparison with seasonal effects. In seasons characterized by cool, consistent conditions, grain yield was maximized by the utilization of all available grain sites. Where assimilate shortages were encountered during grain fill the abortion of grains sites was positively associated with grain yield.


2020 ◽  
Vol 34 (5) ◽  
pp. 666-674 ◽  
Author(s):  
Elizabeth Karn ◽  
Teresa De Leon ◽  
Luis Espino ◽  
Kassim Al-Khatib ◽  
Whitney Brim-DeForest

AbstractWeedy rice is an emerging problem of cultivated rice in California. Infestations of weedy rice in cultivated rice result in yield loss and reduced grain quality. In this study, we aimed to evaluate growth and yield components of a widely grown cultivated rice variety in California in response to weedy rice competition. Greenhouse competition experiments in an additive design were conducted in 2017 and 2018 to determine the growth and yield components of ‘M-206’ rice and five weedy rice biotypes found in California at varying weed densities. M-206 rice initially grew at a faster relative growth rate of 0.53 cm−1 wk−1 under competitive conditions compared with 0.47 cm−1 wk−1 in the absence of weedy rice, but absolute and relative growth rates declined more rapidly under competitive conditions as plants approached maturity. At harvest, M-206 plant height was reduced 13% under competitive conditions, and M-206 tiller number was reduced 23% to 49%, depending on the weedy rice biotype it was competing with. Except for 100-grain weight, the growth traits and grain yield components of M-206 rice were reduced with increasing density of weedy rice. At the highest weed density measured, 40 plants m−2, M-206 rice had yield losses of 69% grain yield plant−1, 69% panicle weight, 59% fresh and dry biomass, 55% grain yield panicle−1, and 54% panicle number. The five evaluated weedy rice biotypes varied widely in early growth rates, height, biomass production, and grain yield, indicating differing competitive strategies. Most weedy rice biotypes produce plants with greater plant height, tiller number, panicle number, and above- and below-ground biomass compared with cultivated rice. Weedy rice biotypes produced 45% to 57% higher grain yield per plant than M-206 rice under competitive conditions.


2008 ◽  
Vol 59 (2) ◽  
pp. 189 ◽  
Author(s):  
G. F. Liu ◽  
J. Yang ◽  
H. M. Xu ◽  
Y. Hayat ◽  
J. Zhu

Grain yield (GY) of rice is a complex trait consisting of several yield components. It is of great importance to reveal the genetic relationships between GY and its yield components at the QTL (quantitative trait loci) level for multi-trait improvement in rice. In the present study, GY per plant in rice and its 3 yield component traits, panicle number per plant (PN), grain number per panicle (GN), and 1000-grain weight (GW), were investigated using a doubled-haploid population derived from a cross of an indica variety IR64 and a japonica variety Azucena. The phenotypic values collected from 2 cropping seasons were analysed by QTLNetwork 2.0 for mapping QTLs with additive (a) and/or additive × environment interaction (ae) effects. Furthermore, conditional QTL analysis was conducted to detect QTLs for GY independent of yield components. The results showed that the general genetic variation in GY was largely influenced by GN with the contribution ratio of 29.2%, and PN and GN contributed 10.5% and 74.6% of the genotype × environment interaction variation in GY, respectively. Four QTLs were detected with additive and/or additive × environment interaction effects for GY by the unconditional mapping method. However, for GY conditioned on PN, GN, and GW, 6 additional loci were identified by the conditional mapping method. All of the detected QTLs affecting GY were associated with at least one of the 3 yield components. The results revealed that QTL expressions of GY were contributed differently by 3 yield component traits, and provide valuable information for effectively improving GY in rice.


Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1657
Author(s):  
Shimaa A. Badawy ◽  
Bassiouni A. Zayed ◽  
Sherif M. A. Bassiouni ◽  
Ayman H. A. Mahdi ◽  
Ali Majrashi ◽  
...  

Rice production under salinity stress is a critical challenge facing many countries, particularly those in arid and semi-arid regions. This challenge could be handled by applying novel approaches to overcome yield limiting factors and improve resource use efficiency. The usage of nanoparticles (NPs) could be a beneficial approach to managing the growing problem of soil salinity. The aim of our study was to investigate the advantageous effects of soaking and foliar application of silicon (Si) and selenium (Se), (NPs-Si at 12.5 mg L−1 and NPs-Se at 6.25 mg L−1) on root characteristics, moropho-physiological traits, and yields of two rice varieties (i.e., Giza 177 as a salt sensitive and Giza 178 as a salt tolerant) grown in saline soil compared to untreated plants (control treatment). Results showed that soaking NPs-Se resulted in the highest value of root thickness for Giza 178 (0.90 mm, 0.95 mm) and root volume (153.30 cm3, 154.30 cm3), while Giza 177 recorded 0.83 mm, 0.81 mm for root thickness and 143.30 cm3, 141.30 cm3 for root volume in the 2018 and 2019 seasons, respectively. Soaking NPs-Se, NPs-Si and foliar application of NPs-Se at BT resulted in the highest relative water content and dry matter, while foliar application of NPs-Si at BT gave the highest leaf area index of rice plants compared to the other treatments. Giza 178 (i.e., salt tolerant variety) significantly surpassed Giza 177 (i.e., salt sensitive variety) in the main yield components such as panicle number and filled grains/ panicle, while Giza 177 significantly exceeded Giza 178 in the panicle weight, 1000-grain weight, and unfilled grains number/ panicle. Soaking NPs-Se and foliar application of NPs-Si at BT resulted in the highest grain yield of 5.41 and 5.34 t ha−1 during 2018 and 5.00 and 4.91 t ha−1 during 2019, respectively. The salt sensitive variety (Giza 177) had the highest Na+ leaf content and Na+/K+ ratio as well as the lowest K+ leaf content during both seasons. Applying nano nutrients such as NPs-Si and NPs-Se improved the yield components of the salt sensitive variety (Giza 177) by enhancing its ion selectivity. Both NPs-Si and NPs-Se had almost the same mode of action to mitigate the harmful salinity and enhance plant growth, and subsequently improved the grain yield. In summary, the application of NPs-Si and NPs-Se is recommended as a result of their positive influence on rice growth and yield as well as minimizing the negative effects of salt stress.


2016 ◽  
Vol 57 ◽  
pp. 67-78
Author(s):  
Pham Thi Thu Ha ◽  
Do Tan Khang ◽  
Phung Thi Tuyen ◽  
Truong Ngoc Minh ◽  
Tran Dang Xuan ◽  
...  

Present study was performed to analysis both physical and chemical properties of rice germplasm and heritability for yield components in combinations. A total of 44 lines/varieties obtained from Cuu Long Rice Research Institute genebank, and 30 F1 generation combinations were evaluated. The results showed that the rice line IR79008-B-11-B-B-1 showed overall good physical characters (head rice, grain length, grain width, chalkiness). In terms of chemical characteristics, three varieties IR75499-73-1-B, OM6162, and OM4900 were found to have good amylose content, gel consistency, protein content, gelatinization temperature, and aroma. A very notable finding was that the cross between OM6162/SwarnaSub1 that low amylose content (20.2%), high gel consistency (78.2 mm), high protein content (8.1%), appropriate gelatinization temperature (scale 5), low chalkiness (level 0), high heritability (0.9) for grain yield trait/cluster, and (0.84) for the number of panicles/cluster. Moreover these characters consist of plant height, panicles lenght, number of panicles/cluster, number of filled grains/panicle, number of unfilled/panicle, and grain yield/ cluster showed moderate to high heritability of mean for combination OM6162/SwarnaSub1. The results suggest that the grain yield trait/cluster and the number of panicles/cluster are important yield contributing traits to rice breeders for selecting ideal combinations for higher yield and quality of next generations.


2019 ◽  
Vol 58 (1) ◽  
pp. 34-43
Author(s):  
R. Hackett

AbstractThere is relatively little recent information regarding the effect of timing of fertiliser N application to spring barley on grain yield and grain protein concentration (GPC) under Irish conditions. The objectives of this work were to examine the effects of a) timing of the first N application to spring barley (at sowing or at crop emergence), b) altering the proportion of the total N allocation that is applied in the first of two applications and c) delaying a portion of the total N dose until after the tillering phase on grain yield and GPC of spring barley. Twenty experiments were carried out over four seasons (2011–2014) in the south and south-east of Ireland. Results indicated that there was little consistent difference, in terms of grain yield or GPC between applying the first N at sowing compared to where the initial N application was made at crop emergence. Similarly, altering the proportion of N applied in the first application, irrespective of whether the first application was at sowing or at crop emergence, had little effect on either yield or GPC. Delaying the application of a portion (0.2) of the total N until after the tillering stage also had little consistent effect on either yield or GPC. It is concluded that where the majority of N is applied to spring barley before the end of the tillering stage, altering the timing of applications or the proportion of the total applied in each application will have limited effect on grain yield or GPC.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11668
Author(s):  
Ke Wu ◽  
Izhar Ali ◽  
Huimin Xie ◽  
Saif Ullah ◽  
Anas Iqbal ◽  
...  

The current farming system in China is heavily reliant on synthetic fertilizers, which adversely affect soil quality and crop production. Therefore, the aim of this study was to assess the effect of different nitrogen (N) and phosphorous (P) fertilizer application rate on the growth, yield, and yield components of rice cultivars in the Binyang, Beiliu and Liucheng sites of southern China in the early (March to July) and late season (August to December). The study consisted of three fertilization regimes—CK (N0P0); N180P90 (180 kg N + 90 kg P2O5 ha−1) and N90P45 (90 kg N ha−1 + 45 kg P2O5)—conducted at each of three different experimental sites with four cultivars (Baixang 139, Y Liangyou 1, Guiyu 9, and Teyou 582). Results showed that the leaf area index (LAI) was 38.8% found higher in Guiyu 9 compared with Baxiang at reduced fertilization (N90P45). N90P45 resulted higher dry matter production at the heading (9411.2 kg ha−1) and maturity (15319.5 kg ha−1) stages in Teyou 582 at Beiliu. Fertilization (N180P90) had higher effective panicle number (4,158,800 panicle ha−1) and grains panicle−1 (113.84 grains) compared with other treatments. Teyou 582 treated with N90P45 and Y Liangyou 1 treated with N180P90 improved seed setting rate average by 82.91% and 72.17% compared with other treatments at Beiliu in both seasons, respectively. N0P0 and N90P45 increased the thousand-grain weight (TGW) of Y Liangyou 1 at Binyang (27.07 g) and Liucheng (27.84 g) during the early and late seasons, respectively. In Beiliu, the N90P45 treatment (6611.7 kg ha−1) of Teyou 582 increased grain yield compared with other treatments. Overall, our results suggested that reducing N and P at the ratio of 90:45 kg ha−1 in Teyou 582 and Y Liangyou 1 could increase rice grain yield and yield components.


1992 ◽  
Vol 32 (3) ◽  
pp. 355 ◽  
Author(s):  
MG Mason

The effect of either burning stubble, or incorporating it in the soil, on the nitrogen (N) fertiliser requirement of the following wheat crop was examined over 10 years (1978-87) in a continuous wheat system at 2 sites (Wongan Hills and Nabawa), and in both continuous wheat and wheat-fallow systems at one site (Merredin). There were significant grain yield increases in response to N fertiliser in all years at Nabawa. At Wongan Hills there was no response in 1978 and 1985, a yield reduction in 1979, and a yield increase in all other years. At Merredin, there was no response in 1980, a yield decrease in 1984 and 1985, and an increase in all other years. In some years grain yield responses were small at Wongan Hills and Merredin. The only significant overall effects of stubble treatment were at Nabawa in 1978 (P<0.01) and 1985 (P<0.05). The interaction between stubble treatment and N rate was significant at Wongan Hills in 1980 and 1981 (P<0.05), and at Merredin in 1981 (P<0.001), 1983, and 1985 (both P<0.05). Response to N fertiliser was higher where the stubble was incorporated than where it was burnt. There was also a tendency for higher optimum economic rates of N fertiliser with stubble incorporated rather than burnt, but differences were not large. At Merredin, the overall yield increase with fallow was significant (P<0.001) in 1979 and 1983. The fallow x N fertiliser rate interaction was significant in all comparison years except 1987. Responses to N were greater in the non-fallow treatments. Soil organic carbon (C) levels were higher with stubble incorporation than where the stubble was burnt, and fallowing resulted in lower organic C. There was a downward trend with time, especially when fallowing was carried out. Effects on total N levels in the soil were similar to those for organic C but were less marked. The study indicates that at a level of stubble residues of 1-3 t/ha with continuous wheat in this winter rainfall environment in Western Australia, stubble treatment is unlikely to be a major factor in determining the rate of N fertiliser required for a wheat crop.


2020 ◽  
pp. 21-27
Author(s):  
Weldegebriel Gebrehiwot ◽  
Tewolde Berhe ◽  
Tsadik Tadele ◽  
Kinfe Tekulu ◽  
Geberesemaeti Kahsu ◽  
...  

A field experiment was carried out to evaluate different rates of vermicompost, and inorganic NPS(Nitrogen-Phosphate Fertilizer With Sulphur) fertilizers for wheat production in 2015-2017 main cropping seasons at L/machew district of the Tigray Regional State. There were five systematically combined rates of vermicompost and one rate of NPS treatments during the study. The experimental design was randomized complete block with three replications. Surface soil samples were collected before planting to analyze selected soil properties. The textural class of the soil was clay. The pH of the soil was rated under moderately acidic. Available P was rated under medium in most of the experimental sites while total N was low in all experimental sites.  The treatments significantly affected crop phenology, yield and yield components of wheat. Thus tallest plant height was found from treatments that received 100kg/ha NPS, followed by 8.75t/ha vermicompost which resulted in (73.25cm) while the shortest plant (62.73cm) was obtained from control plots, respectively. Highest mean wheat grain yield (2642.8kg/ha) was obtained in response to 100kg NPS from inorganic fertilizer application followed by the second highest dose of vermicompost (7t/ha) with grain yield of 2620 kg/ha.  At the wheat plants grown in plot received vermicompost compost at 7t/ha of vermicompost increased the grain yield by 67.78% over the control. Though highest grain yield was obtained from highest dose of vermicompost the partial budget analysis shows that the highest marginal rate of return (456) was obtained from 3.5t/ha VC ha-1 plus 100kg/ha urea at the study area.


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